1. Field
The present application generally relates to hand-held saws for cutting delicate designs on materials such as metal and wood. More particularly, the present application relates to a hand-held saw having a C-shaped frame for a tensioned blade, such as a coping saw or a fret saw, that allows a user to cut delicate designs accurately.
2. Related Art
When cutting with a hand-held saw, friction between the saw blade of the hand-held saw and the material being cut creates a resistance to any movement of the saw. To continue cutting, a user typically overcomes the resistance by exerting pressure on the hand-held saw and the saw blade. Since the saw blade is in contact with the material being cut, the force exerted by the user tends to bend the blade. A bent saw blade produces inaccurate cuts, and will eventually break if it is sufficiently bent.
A saw blade is typically coupled to a saw frame under tension in order to reduce the amount of bending, or flex, experienced by the blade. However, the tensioning of a saw blade creates an opposite pressure against the saw frame. Due to the elongated bow shape of the typical saw frame, this pressure tends to compress the side of the saw frame that is coupled to the blade. As the saw frame compresses, the distance between the distal and proximal ends of the saw frame is reduced, and the tensile force exerted on the saw blade is proportionately decreased. Thus, compression of the saw frame reduces blade tension, and is therefore undesirable.
The amount by which a saw frame compresses depends on the design and the material of the saw frame. A typical saw frame is made from a metal rod, bent into an elongated bow shape, commonly referred to as a “C-shape.” FIG. A shows graphically one example of a hand-held saw made from a metal rod that is bent and flattened. The bending process introduces metal fatigue and internal deformities in the saw frame, and reduces the overall rigidity of the saw frame. Thus, saw frames produced by bending rely on, but do not take full advantage of, the inherent strength of the material employed.
Some hand-held saws address the problem of frame rigidity by using heavier metals, or by using additional amounts of metal, in their construction. Both of these practices increase the weight of the saw frame, which not only increases the overall weight of the resulting saw, but also upsets the weight balance of the saw frame in relation to the lighter saw blade. These results are undesirable. First, a heavier saw is more physically demanding of its user. Second, it is difficult for a user to position the saw blade of a frame-heavy saw to perform a delicate cut.